What is the difference between demand and quantity demanded of a product, say milk?

Your take on decision making process

Which ranks these careers that employers are most likely to hire from the least to the greatest?

The purpose of safety stock is to: a. eliminate the possibility of a stockout. b. control the likelihood of a stockout due to variable demand and/or lead time. c. eliminate the likelihood of a stockout due to erroneous inventory tally. d. protect the firm from a sudden decrease in demand. e. replace failed units with good ones.